There doesn't appear to be an issue with fires in spent fuel ponds according to this article I found (below), and the discussions I've been having here:
http://bravenewclimate.com/2011/03/18/fukushima-radiation-tsunamis/
Spent fuel heatup following loss of water during storage. [PWR; BWR]
Benjamin, A.S. ; McCloskey, D.J. ; Powers, D.A. ; Dupree, S.A.
Abstract: An analysis of spent fuel heatup following a hypothetical accident involving drainage of the storage pool is presented. Computations based upon a new computer code called SFUEL have been performed to assess the effect of decay time, fuel element design, storage rack design, packing density, room ventilation, drainage level, and other variables on the heatup characteristics of the spent fuel and to predict the conditions under which clad failure will occur. Possible storage pool design modifications and/or onsite emergency action have also been considered.
http://www.osti.gov/bridge/product.biblio.jsp?osti_id=6272964
A commenter posted:
>>Importantly, reading the documents introduction
>>& conclusion section seems to indicate that
>>there is a “decay time” of 5 to 150 days after the
>>BWR fuel assemblies are put in the spent fuel
>>pond, after which the fuel assemblies do not
>>reach the critical 850-950C following a complete
>>water drain.
The article seems to suggest it isn't a burning issue, although the radiation would be quite locally intense (within the pool itself) until it is recovered by water. Nothing would be leaking about into the air though. If anyone has a different take on the article share them.